The invention concerns aqueous dispersions of copolymers based on (meth)acrylic acid derivatives, their preparation and use, for example, in the production of thermosetting or stoving enamels. Enamels produced this way yield coats of increased surface hardness, with increased elasticity, extensibility and substrate adhesion.
It is known that aqueous dispersions of (meth)acrylic ester copolymers, which contain, optionally, other monomer units derived, for example, from styrene, and which are thermosettable by the incorporation of comonomers containing hydroxyl groups, such as hydroxypropyl methacrylate, and by the addition of a cross-linking agent, like hexamethoxymethyl melamine, can be used as binders for stoving enamels. Enamels containing these binders frequently have a high surface hardness, but they are generally either extremely brittle, or they are flexible so that the undercoat can still be deformed, for example, without the enamel chipping off, but their surface hardness is then insufficient.